Turlock Basin facts for kids

The Turlock Basin is a special underground area in California. It's part of the much larger San Joaquin Valley groundwater basin. Think of it like a giant sponge under the ground that holds water. The San Joaquin Valley basin is the biggest groundwater basin in California, covering about 13,700 square miles. The Turlock Basin itself is about 542 square miles (or 347,000 acres).

This underground water storage, called an aquifer, is found in Merced and Stanislaus counties. It's located in the Central Valley. The Tuolumne River is to its north, the Merced River to its south, and the San Joaquin River to its west. To the east, you'll find the Sierra Nevada foothills. The Turlock Basin is also east of the city of Turlock.

Much of the water in the San Joaquin Basin is in newer alluvial material (like sand and gravel left by rivers). However, the Turlock Basin's water is in older alluvial deposits. Sadly, some parts of the San Joaquin Basin have used too much water, causing levels to drop. Also, agricultural water can carry pollutants into the ground, making the water quality poor.

How Land Use Affects Water Quality

Most of the land above the Turlock Basin is used for growing crops. More than 250,000 acres are used for irrigated farms. From 1952 to 2006, cities and towns grew a lot. Urban areas increased from 4,000 to 20,000 acres, especially in the Turlock Irrigation District.

Scientists have found some things to watch out for:

• In 2006, tests on 513 wells showed that 39 of them had too many contaminants. These included things like nitrates, pesticides, and VOCs (volatile organic carbons). The amount was above the maximum safe level (MCL).
• A study in 2016 showed that groundwater levels in 38 wells had dropped over 40 years (from 1971 to 2011).

The city of Turlock gets all its water supply for domestic use from this underground water. The water often contains a type of sodium sulfate. Some local wells have even been closed in the past because of a pesticide called DBCP.

When the groundwater was tested, 120 different contaminants were found. In an area that depends on groundwater for drinking, these contaminants reduce the usable supply. The main problems are arsenic and nitrates. Arsenic is a natural element, but a 2014 study found 11.8 ppb (parts per billion) of arsenic in the drinking water.

Nitrate levels have also gone up because of farming, fertilizers, and growing cities. Nitrates were found at 45 mg/L (milligrams per liter). High nitrate levels can be dangerous, especially for babies, causing illness or even death. This shows how human activities can harm the very water we need to survive.

Taking Care of Our Water: The Turlock Plan

The Turlock Groundwater Management Plan is a set of goals to protect this important water source. Here's what they aim to do:

• Keep enough water in the underground basin.
• Protect the quality of the groundwater. They also try to stop existing contaminants from spreading.
• Watch how much groundwater is taken out. This helps prevent the land from sinking, which is called subsidence.
• Encourage using both groundwater and surface water together. This is called "conjunctive use."
• Support and encourage everyone to save water. This is called "water conservation."
• Find and support new ways to get water. They also teach people about the benefits of cleaning and reusing water, known as "water recycling."
• Keep working together with all the groups and people involved in the Turlock Basin.